Cycle 24 Sunspots count continues to underperform early forecasts. Chief forecaster, David Hathaway, Ph.D., Heliospheric Team Leader, NASA Marshall Space Flight Center, Huntsville, Alabama has frequently revised his forecast of maximum monthly average Sunspot count. A look at the lowering of the NASA forecast over the years:
Before I pile it too heavily on Dr. Hathaway, most of the experts were as wrong as he was. One of the few that accurately forecast Cycle 24 was Dr. Lief Svalgaard of the Helioseismic and Magnetic team of Stanford’s Solar Dynamics Observatory (SDO), Svalgaard predicted 75 as the maximum number in 2004 and has since revised it downward to 72.
Show below is the Cycle 24 recorded Sunspot monthly average numbers through July 2011 versus the current NOAA forecast of 90.
Before you begin to question my grasp of consistency in numbers, please be aware that the Sunspot number is measured several different ways. The folks in business recognize this and have put together a team to try to bring about uniformity. One of the more obvious questions is —are we reading more sunspots now because we have much better optics? The following abstract from this program lays out some of the problems.
The Sunspot number (SSN) record (1610-present) is the primary time sequence of solar and solar-terrestrial physics, with application to studies of the solar dynamo, space weather, and climate change. Contrary to common perception, and despite its importance, the international sunspot number (as well as the alternative widely-used group SSN) series is inhomogeneous and in need of calibration. We trace the evolution of the sunspot record and show that significant discontinuities arose in ~1885 (resulting in a ~50% step in the group SSN) and again when Waldmeier took over from Brunner in 1945 (~20% step in Zürich SSN). We follow Wolf and show how the daily range of geomagnetic activity can be used to maintain the sunspot calibration and use this technique to obtain a revised, homogeneous, and single sunspot series from 1835-2011.
Where do we go from here?
Find and Digitize as many 19thcentury geomagnetic hourly values as possible
Determine improved adjustment factors based on the above and on model of the ionosphere
Co-operate with agencies producing sunspot numbers to harmonize their efforts in order to produce an adjusted and accepted sunspot record that can form a firm basis for solar-terrestrial relations, e.g. reconstructions of solar activity important for climate and environmental changes
To learn more about sunspot counting click here.
As the magnetic fields are what drive sunspots, here is a current look at Sun’s north and south magnetic fields:
Chart Courtesy of Wilson Solar Observatory
It is obvious that Cycle 24 is different from the Cycles 21, 22 and 23 that precede it. The magnetic field strength is much weaker and angle of approach to the X axis (0 microTesla line) is very much steeper than that of Cycle 24. Click here, here and here for further discussion of the magnetic field.
How about a look ahead to cycle 25 and beyond. I don’t know enough to have much confidence in this forecast Ed Fix, but David Archibald seems to think it is viable. Click here for more info:
The green line is the solar cycle record from 1914 to 2010, with alternate cycles reversed. Solar Cycles 19 to 23 are annotated. The red line is the model output, from which the lengths of individual solar cycles in the mid-21st Century can be calculated.
Mr. Fix has Cycle 25 duplicating the current Cycle 24. Cycles 26,and 27 are about half again as large as 24 and 25. Even so his forecast for Cycles through 28 are all considerably less active than Cycles 18 through 23. Does this mean an extended global cooling?